Photodiodes sensitive to ultraviolet light are known from EP 0 296 371 A1 The known photodiodes sensitive to ultraviolet light are as a rule broadband devices and have relatively poor spectral selectivity.
Color sensors comprising a combination of two photodiodes with different spectral sensitivities are known for flame monitoring from the publication, "Combustion Detection With A Semiconductor Color Sensor," N. Kako et al, SENSORS AND ACTUATORS, 4 (1983), pages 655 to 660.
It is an object of the present invention to realize photodiodes sensitive to ultraviolet light with a spectral selectivity that is at least one order of magnitude better than that of the known photodiodes which are sensitive to ultraviolet light.